Design of a Novel Air Bearing Workbench for Rotary Ultrasonic Drilling of Advanced Ceramics

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Liping Liu ◽  
Bin Lin ◽  
Fengzhou Fang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Cutting Force ◽  
Air Bearing ◽  
The Novel ◽  
Advanced Ceramics ◽  
Air Damping ◽  
Ultrasonic Drilling ◽  
Rotary Ultrasonic Drilling

A novel air bearing workbench used in rotary ultrasonic drilling of advanced ceramics was designed to constantly and sensitively control the cutting force. Compared with traditional feed systems, the novel air bearing workbench features an aerostatic guide and a pneumatic actuator, so that it only overcomes the air damping when the cutting force is balanced. Thus, it can sensitively and constantly control the cutting force for rotary ultrasonic drilling of advanced ceramics. The aerostatic guide, which determines the eccentric bearing capacity and stiffness of the workbench, is the most important part. The forces applied on the aerostatic guide faces were analyzed to calculate the bearing capacity and stiffness of the workbench using varying gas film thicknesses with finite element method (FEM). Based on the result of the analysis, the best gas film thickness of the aerostatic guide was designed to be 30 μm. The real eccentric bearing capacity and stiffness of the workbench were measured. The error between experimental results and the FEM results was within 12%.

Influence Coefficient of Filler Plates in Built-Up Cruciform Section Members Formed by Two Equal-Leg Angles

2011 ◽  
Vol 243-249 ◽  
pp. 584-591
Author(s):  
Long Yu Yang ◽  
Zheng Liang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
High Voltage ◽  
Cross Sections ◽  
Radius Of Gyration ◽  
Influence Coefficient ◽  
Transmission Towers ◽  
Minimal Radius ◽  
Extra High Voltage

The built-up cruciform section formed by two equal-leg angles has been widely applied in extra high voltage(EHV) transmission towers, however, domestic codes provide structure requirement and overlook the influence of multi filler plates to members’ bearing capacity. For the purpose of this, a pin end experiment covering 3 different cross sections(Q420, L160*12, L160*14 and L160*16) and 7 different slendernesses(25~55) has been run. This experiment contains totally 21 specimens. Furthermore, large amounts of models have been analysis by finite element method whose parameters contain variety b/t, λ, filler plate intervals and forms, amount of bolts in filler plate. A recommended formula is given for evaluating the influence of filler plates. The results show: multi filler plates enhance bearing capacity slightly for members with λ less than 35, and the better interval for filler plates is 10i-40i(i is the minimal radius of gyration); filler plates do not work well when b/t of the member is extreme large or small, a propositional b/t range for this kind of member is 11-16; the amount of bolts in filler plate has tiny influence on members’ bearing capacity; the recommended formula is applicable and feasible for design.

scholarly journals Cutting Force Predication Based on Integration of Symmetric Fuzzy Number and Finite Element Method

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Zhanli Wang ◽  
Yanjuan Hu ◽  
Yao Wang ◽  
Chao Dong ◽  
Zaixiang Pang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cutting Force ◽  
Fuzzy Number ◽  
Experimental Result ◽  
The Finite Element Method ◽  
Mechanical Coupling ◽  
Fuzzy Function ◽  
Nonuniform Stress Field ◽  
Element Method

In the process of turning, pointing at the uncertain phenomenon of cutting which is caused by the disturbance of random factors, for determining the uncertain scope of cutting force, the integrated symmetric fuzzy number and the finite element method (FEM) are used in the prediction of cutting force. The method used symmetric fuzzy number to establish fuzzy function between cutting force and three factors and obtained the uncertain interval of cutting force by linear programming. At the same time, the change curve of cutting force with time was directly simulated by using thermal-mechanical coupling FEM; also the nonuniform stress field and temperature distribution of workpiece, tool, and chip under the action of thermal-mechanical coupling were simulated. The experimental result shows that the method is effective for the uncertain prediction of cutting force.

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